The present invention relates to a liquid crystal display device and a defect repairing method for the same.
Recently, liquid crystal display devices have been practically used in the fields of OA equipment and AV equipment owing to their advantages in compactness, small weight and size and small consumption power. In particular, an active matrix liquid crystal display device including a switching element (active device) in each picture element is capable of producing a fine dynamic display and hence is used as a display for a variety of equipment.
In an active matrix liquid crystal display device, picture elements are composed of picture element electrodes provided in the form of a matrix, a counter electrode opposing the picture element electrodes and a liquid crystal layer disposed therebetween. Each of a plurality of picture elements is controlled in its display state in accordance with an electric signal supplied through the switching element.
In an active matrix liquid crystal display device, short-circuit may be caused between the picture element electrode and the counter electrode or the like due to a conducting debris mixed in the liquid crystal layer. A normal voltage cannot be applied to a picture element in which the short-circuit through the picture element electrode is caused, resulting in a display defect that desired display cannot be obtained.
As a method for repairing a display defect, Japanese Laid-Open Patent Publication No. 4-178622 discloses a defect repairing method in which a photoresist including a black pigment is applied on the face of a glass substrate and a shield film is formed by exposing and curing a portion of the photoresist positioned on merely a picture element suffering from a display defect, so as to change a bright defect into an opaque point (dark defect). An dark defect is less visually recognized than a bright defect and hence merely slightly affects the display quality.
The present inventors have, however, found that a display defect cannot be effectively repaired by the defect repairing method disclosed in Japanese Laid-Open Patent Publication No. 4-178622.
In the defect repairing method of Japanese Laid-Open Patent Publication No. 4-178622, the entire picture element suffering from a bright defect is covered with a shield film formed so as to change the entire picture element into an opaque point, and therefore, the entire picture element having the display defect cannot make contribution to the display.